Conventionally, deformation or breakdown of a pad electrode or breakdown and the like of a region under the pad electrode becomes a problem. They are caused by bonding impact such as pressurization or supersonic vibration of a bonding connection, when an aluminum wire or a gold wire is bonded and connected to the pad electrode as an external output electrode of the semiconductor device.
To improve failure of the pad electrode attributed to the bonding impact, as shown in FIG. 15, a first prior art (i.e., Japanese Laid-Open Patent Publication No. S63-161634) discloses a construction for absorbing the bonding impact by forming a planar shape of a pad electrode 71 to be a network construction in such a manner that a through hole 74k is formed in the pad electrode 71 made of aluminum or aluminum alloy.
However, when a size of the pad electrode is the same, a problem occurs that connection strength of a bonding portion becomes smaller. This is because a wire is not mechanically connected to a field oxide film exposed on a bottom of the through hole in this construction. The wire is embedded in the through hole 74k when the bonding connection is performed.
Further, in the manufacturing process of the semiconductor device, there is a problem that the network construction of the pad electrode 71 formed by the through hole 74k is broken down when a needle is placed (i.e., a probe operation is performed) in a test process performed before the bonding connection.
Furthermore, a second prior art (i.e., Japanese Laid-Open Patent Publication No. 2001-156070, which corresponds to US Patent Application Publication No. 2005/0014356-A1) shown in FIG. 16 is proposed as another prior art for improving failure of the pad electrode attributed to the bonding impact. According to the second prior art, a support construction 83s is formed by opening a part of a terminal insulation protection film 83. The film 83 is formed of dielectric material on a pad electrode 82, which is made of electric conductive material such as aluminum. The bonding impact is absorbed by bonding the pad electrode 82 through the support construction 83s. 
However, in this construction, the pad electrode 82 is bonded and connected through the support construction 83s. Therefore, there is a problem that connection strength of a bonding portion is reduced, similar to the first prior art. Further, since a needle is placed on the pad electrode 82 through the support construction 83s in case of the probe operation, a problem occurs that failure of electric connection between the pad electrode 82 and the needle is caused.
As described above, in addition to the problem that failure of the pad electrode is caused by the bonding impact, in the prior art for absorbing and reducing the bonding impact, there are other problems such as reduction of the connection strength of the bonding portion, breakdown of the pad electrode construction in case of the probe operation, and failure of electric connection.